Study of Pressure Propagation Characteristics to Determine Stress Sensitivity of Low-Permeability Gas Reservoir

Abstract

The permeability sensitivity of formation is one of the primary causes of damage to low-permeability reservoir. Experiments were conducted on change in pressure propagation characteristics with reference to matrix rock (core) samples taken from a low-permeability reservoir in Changqing oilfield, China. Based on the experimental results, pressure propagation values were obtained using CMG numerical simulation software that takes account of permeability sensitivity of the formation. The experimental and simulation results indicate that gas well productivity in lowpermeability gas reservoir cannot be increased significantly by increasing pressure difference in low-permeability gas reservoir. With increase of permeability sensitivity of formation stressed state the pressure propagation coefficient decreases, pressure propagation delay increases, and steady gas production time becomes shorter with higher gas flow rate.